With warm-hearted and friendly promotion by our Japanese friends Prof. - sushi Ohori, Prof. Tetsuo Ida, and Prof. Zhenjiang Hu, and other distinguished professors and scholars from countries and regions such as Japan, South Korea, Singapore, and Taiwan, the 1st Asian Symposium on Programming Languages andSystems(APLAS2003)tookplaceinBeijing.Wereceived76papers,among which 24 were selected for the proceedings after serious evaluation, which fully demonstrates the high quality of the collected papers. I hereby, on behalf of the Program Committee and the Organization Committee of the symposium, would like to extend the warmest welcome and hearty thanks to all colleagues who attended the symposium, all scholars who generously contributed their papers, and all those who were actively dedicated to the organization of this symposium. Over the past decade, the Asian economy has undergone rapid development. Keeping pace with this accelerated economic growth, Asia has made great he- way in software, integrated circuits, mobile communication and the Internet. All this has laid a ?rm material foundation for undertaking theoretical research on computer science and programming languages. Therefore, to meet the incr- sing demands of the IT market, great opportunities and challenges in advanced research in these ?elds. I strongly believe that in the coming future, with the persistent e?orts of our colleagues, the Asian software industry and research on computer science will be important players in the world economy, on an equal footing with their counterparts in the United States and Europe.

The Fourth International Workshop on Database Programming Languages - Object Models and Languages (DBPL-4) took place in Manhattan, New York City, 30 August-1 September 1993. The areas of interest and the format of DBPL-4 focused on the integration of programming languages, object models, type systems and database systems. As in the previous DBPL workshops, the setting was informal, allowing the participants to actively discuss and argue about the ideas presented in the talks. The comments and remarks made by the participants during and after the presentations were taken into account in the preparation of the final versions of the papers. The result, we believe, is a set of excellent papers. The DBPL sequence is closely related to the sequence of International Workshops on Persistent Object Systems (POS), first started in 1985. While the DBPL workshops focus on language and model issues, the POS workshops have focused on implementation issues; thus the two sequences complement each other. Many researchers participate in both workshop series. The eight sessions of the technical program of DBPL-4 were as follows: 1. Bulk types and their query languages (two sessions). 2. Object models and languages. 3. Data types with order. 4. Mechanisms to support persistence, reflection, and extensibility. 5. Query optimization and integrity constraints. 6. Logic-based models. 7. Implementation and performance issues.

This book constitutes the refereed proceedings of the 4th Asian Computing Science Conference, ASIAN'98, held in Manila, The Philippines, in December 1998. The 17 revised full papers presented were carefully reviewed and selected from a total of 43 submissions. Also included are a few invited contributions. Among the topics covered are automated deduction, proof theory, rewriting systems, program semantics, distributed processing, algorithms, and graph-theoretical aspects.

The Fourth International Workshop on Database Programming Languages - Object Models and Languages (DBPL-4) took place in Manhattan, New York City, 30 August-1 September 1993. The areas of interest and the format of DBPL-4 focused on the integration of programming languages, object models, type systems and database systems. As in the previous DBPL workshops, the setting was informal, allowing the participants to actively discuss and argue about the ideas presented in the talks. The comments and remarks made by the participants during and after the presentations were taken into account in the preparation of the final versions of the papers. The result, we believe, is a set of excellent papers. The DBPL sequence is closely related to the sequence of International Workshops on Persistent Object Systems (POS), first started in 1985. While the DBPL workshops focus on language and model issues, the POS workshops have focused on implementation issues; thus the two sequences complement each other. Many researchers participate in both workshop series. The eight sessions of the technical program of DBPL-4 were as follows: 1. Bulk types and their query languages (two sessions). 2. Object models and languages. 3. Data types with order. 4. Mechanisms to support persistence, reflection, and extensibility. 5. Query optimization and integrity constraints. 6. Logic-based models. 7. Implementation and performance issues.

Abstract: "This paper develops a typed calculus for contexts i.e., lambda terms with 'holes'. In addition to ordinary lambda terms, the calculus contains labeled holes, hole abstraction and context application for manipulating first-class contexts. The primary operation for contexts is hole filling which captures free variables. This operation conflicts with the capture-avoiding substitution of the lambda calculus, and a straightforward mixture of the two results in an inconsistent system. We solve this problem by defining a type system that precisely specifies variable-capturing properties of contexts as well as their types, and systematically performing bound variable renaming. This enables us to define a reduction system that properly integrates full [beta]-reduction and fill-reduction. For this calculus, we prove the subject reduction property and Church-Rosser property. This context calculus will serve a basis for developing programming languages with advanced features that call for manipulation of open terms such as flexible first-class modules."

Abstract: "We define a polymorphic unboxed calculus as an abstract machine for implementing polymorphic languages, and develop an algorithm to translate ML into this calculus. These two results provide a formal operational semantics for efficient compilation of ML style polymorphic languages. As in statically typed monomorphic languages, run- time objects in the unboxed calculus have their natural representations according to their types, and are manipulated by the operations specialized to the representation. In particular, multi-word constants such as floating point numbers are unboxed. The calculus is name-free and supports efficient value binding by integer representation of variables. Different from de Bruijn indexes, our integer representation of a variable corresponds to the actual offset to the value in a run-time environment consisting of unboxed objects of various sizes. The calculus also supports polymorphism through an abstraction mechanism over argument sizes. Translation of ML into the unboxed calculus is done by using type information obtained through type inference. At the time of polymorphic let binding, the necessary size abstractions are inserted so that a polymorphic function is translated into a function that is polymorphic not only in the type of the argument but also in its size. The ML type system is shown to be sound with respect to the operational semantics realized by the translation."